⁹Felcher, S., Stinner, D. J., Krueger, C. A., Wilken, J. M., Gajewski, D. A., & Hsu, J. R. Falls in a Young Active Amputee Population: A Frequent Cause of Re-hospitalization? Military Medicine. Accepted (2/4/2015).

Falls occur in up to 50% of amputees within a single year of their operation and up to 40% of these falls result in injury.  This study determined incidence, prevalence, fall characteristics, and risk factors for falls that resulted in re-hospitalization in young (average age 25 years) Service Members with amputation. Most falls occurred within the first six months following definitive amputation, and 75% of rehospitalized patients required at least one surgery. Infectious complications had the most significant morbidity and individuals that delayed evaluation were significantly more at risk of an infectious complication than those that presented within one day from a fall. This study is the first to report a relationship between time to medical care and infectious complication, and emphasizes the need for at risk patients to seek early medical attention to minimize the risk of infection and subsequent need for surgical intervention.⁹

¹⁰Sturdy J; Gates DH; Darter BJ; Wilken JM. (2014). Assessing preparative gait adaptations in persons with transtibial amputation in response to repeated medial-lateral perturbations.  Gait Posture. Mar; 39(3):  995-998..

Preventing loss of balance in individuals with transtibial amputation through rehabilitation interventions is important.  To validate fall prevention and balance therapies, methods to assess gait stability were developed by exposing patients to perturbations while walking on a treadmill.  Data from six healthy young participants with transtibial amputation revealed that the only consistent postural adjustment made as a result of medial-lateral perturbations was a significantly lowered center of mass height.¹⁰

¹¹Sheehan, R. C., Beltran E. J., Dingwell, J. B., & Wilken, J. M. (2015). Mediolateral Angular Momentum Changes in Persons with Amputation During Perturbed Walking. Gait & Posture, 2015 Mar; 41(3):795-800. doi: 10.1016/j.gaitpost.2015.02.008

Young active individuals with unilateral transtibial amputation (TTA) and able-bodied controls were exposed to destabilizing movement of the walking surface within a virtual reality environment.  Individuals with TTA are less able to respond when their balance is challenged and rely on altered movement of their intact limb to maintain stability. Gait training which integrates physical perturbations may help to prevent falls and lessen demand on the intact limb.¹¹

⁸Russell Esposito E; Rodriguez KM; Rabago CA; Wilken JM. (2014). Does unilateral transtibial amputation lead to greater metabolic demand during walking? JRRD, 51(8): 1287-1296.  Doi: 10.1682/jrrd.201406.0141

Previous literature reports greater metabolic demand of walking following transtibial amputation. However, most research focuses on relatively older, less active, and often dysvascular amputees, compared to a population of Service Members.  This is the first study to find equivalent metabolic demands between young, active adults with a unilateral lower limb amputation and able-bodied controls across a wide range of walking speeds.⁸

¹⁴Russell Esposito E; Wilken JM. (2014). Biomechanical risk factors for knee osteoarthritis when using passive and powered ankle-foot prostheses.  Clinical Biomechanics, 29(10): 1186-1192.  Doi: 10.1016/j.clinbiomech.2014.09.005

Knee osteoarthritis in the uninjured limb is problematic for individuals with amputations.  Push-off power from the amputated side is a key component to reducing knee joint loading on the sound limb during walking.  In this study,  young individuals with transtibial amputation displayed few biomechanical risk factors for knee osteoarthritis development in these early stages of prosthetic use.  Use of a powered ankle–foot prosthesis, however, offered biomechanical benefits that may mitigate overuse of the sound limb over time.¹⁴

¹⁵Bulzacchelli, M. T., Sulsky, S. I., Rodriguez-Monquio, R., Karlsson, L. H., & Hill, M. O. Injury during U.S. Army basic combat training: A systematic review of risk factor studies. American Journal of Preventative Medicine, 47(6):813-822. doi: 10.1016/j.amepre.2014.08.008 PMID: 25455122

Approximately one quarter of men and half of women in U.S. Army basic combat training experience an injury. Preventing basic these injuries would reduce associated human and economic costs and discharges from the Army. This study systematically reviews the literature on risk factors for injury during U.S. Army basic combat training.The findings were that smoking and low physical activity increase the risk of injury.¹⁵

¹⁶Bulathsinhala, L., Hill, O. T., Scofield, D. E., Haley, T. F., & Kardouni, J. R. (2015). Epidemiology of Ankle Sprains and the Risk of Separation From Service in US Army Soldiers. Journal of Orthopaedic & Sports Physical Therapy, 2015 Jun, 45(6):477-484. doi: 10.2519/jospt.2015.5733

Ankle sprains are one of the most common musculoskeletal injuries in physically active people and have been identified as the most common foot or ankle injury in active-duty Army personnel, with a rate of 103 sprains per 1000 soldiers per year. The purpose of this study was to report the incidence rate of ankle sprains in active-duty soldiers and to examine if soldiers who sustain ankle sprain injuries are more likely to leave the Army than those who do not sustain an ankle sprain. The results showed that recurrent ankle injuries may independently contribute to reducing a Service Members length of service and preventing recurrent injury is of paramount importance.¹⁶

¹⁷Sulsky, S. I., Karlsson, L. H., Bulzacchelli, M. T., Luippold, R. S., Rodriguez-Monquio, R., Bulathsinhala, L., & Hill, O. T. (2014). Methodological challenges of using U.S. Army administrative data to identify a cohort of basic combat trainees and descriptive analysis of trends in characteristics that are potential risk factors for training-related injury. Military Medicine, 2014 Dec, 179(12):1487-1496. doi: 10.7205/MILMED-D-14-00007

Training-related injury is a threat to military health and readiness. This article describes challenges of using administrative data to identify a trainee cohort and describes demographic and training characteristics across the five Basic Combat Training locations. This study found that the use of secondary data for evaluating military injury rates is difficult and careful approaches to data acquisition and processing are of paramount importance.¹⁷

¹⁸Hruby A., Hill, O. T., Bulathsinhala, L., McKinnon, C. J., Montain, S. J., Young, A. J., & Smith, T. J. (2015). Trends in overweight and obesity in soldiers entering the US Army, 1989-2012. Obesity (Silver Spring), 2015 Mar, 23(3):662-670. doi: 10.1002/oby.20978

The US Army recruits new soldiers from an increasingly obese civilian population. The change in weight status at entry into the Army between 1989 and 2012 and the demographic characteristics associated with overweight/obesity at entry were examined. Demographic characteristics associated with being overweight or obese should be considered when developing military-sponsored weight management programs for new soldiers. The prevalence of overweight and obese in the US Army is increasing and is a challenging adverse secondary health effect in injured servicemembers.¹⁸

¹⁹Howell AF, Pruziner AL, Andrews AM. (2015). Use of Predictive Energy Expenditure Equations in Individuals with Lower Limb Loss at Seated Rest. Journal of the Academy of Nutrition and Dietetics, 115(9), 1479-1485.

Changes in metabolism pose inherent challenges for an amputee population, however there is little published data on the energy requirements for this population.  The present study compared measured values of resting energy expenditure (REE) and compared it to multiple established estimation equations for Service members with and without traumatic lower limb loss.  While all equations tended to under or over-estimate REE for both groups, the 25 kcal/kg estimate had a more even distribution of disagreement for individuals with and without limb loss. These findings offer clinical support that the caloric intake recommendations for young, active individuals with limb loss should be the same as those without limb loss.¹⁹

⁵Russell,E., Blanck,R., Guckert,N., Hsu,J., Wilken,J., (2014) How Does Ankle-Foot Orthosis Stiffness Affect Gait Following Limb Salvage? Clinical Orthopaedics and Related Research, 472(10):3026-3035. doi: 10.1007/s11999-014-3661-3

⁶Haight, D. J., Russell Esposito, E., & Wilken, J. M. (2014). Biomechanics of Uphill Walking Using Custom Ankle-Foot Orthoses of Three Different Stiffnesses. Gait & Posture, 41(3):750-756. doi: 10.1016/j.gaitpost.2015.01.001

The stiffness of an ankle-foot orthosis is a design feature that may offer biomechanical benefits to gait.  However, few differences in lower extremity mechanics were found across a 40% range of AFO stiffness when walking on level ground.⁵  A second study compared compliant, neutral and stiff ankle-foot orthoses during uphill walking. There was a general lack of biomechanical differences across a 40% range of strut stiffness when walking up inclines.⁶  These results suggest that orthotists do not need to invest large amounts of time identifying optimal device stiffness for patients who use dynamic AFOs for low-impact activities such as walking on level ground.  Future studies are planned to determine if choosing a stiffer strut may more readily translate to higher-impact activities and offer less chance of mechanical failure.

¹²Russell Esposito E., Aldridge Whitehead J. M., & Wilken J. M. Step-to-Step transition work during level and inclined walking using passive and powered ankle-foot prostheses. Prosthetics and Orthotics International. 2015 Jan 1. [Epub ahead of print]

New powered ankle–foot prostheses can aid in push-off capabilities, which may reduce metabolic demands compared with passive devices, especially on varying terrains. During the transition from the prosthetic limb to the sound limb, powered prosthetic devices performed equally well to passive devices on inclines and generated more mechanical work than passive devices on level ground. This resulted in a lower metabolic cost of walking, which suggests that powered ankle prostheses may delay fatigue for individuals with transtibial amputation on level terrain.¹²

¹³Pickle NT; Wilken JM; Whitehead JM; Neptune RR; Silverman AK. (2014)  Whole-body angular momentum during stair walking using passive and powered lower-limb prostheses.  J Biomech, 47(13): 3380-3389. Doi: 10.1016/j.jbiomech.2014.08.001

This study evaluated dynamic balance in individuals with a transtibial amputation using powered and passive prostheses as they ascended and descended stairs.  Service Members with an amputation were less stable during prosthetic limb stance compared to able-bodied individuals during stair ascent.  Walking stability was not different when comparing the passive and powered prostheses during stair ascent or descent. Individuals with a transtibial amputation are less stable during stair walking compared to able-bodied individuals. A powered ankle-foot prosthesis provides no distinct advantage over a passive prosthesis in maintaining balance during stair walking.¹³

²Dearth CL. Eighth symposium on biologic scaffolds for regenerative medicine. Regen Med. 2014;9(5):569-72. doi: 10.2217/rme.14.41.

The use of biologic scaffolds (e.g., extracellualar matrix materials) to facilitate restoration of tissue form and function after injury has been successfully translated to the clinic. Every two years, a symposium is held regarding the use of biologic scaffolds for regenerative medicine applications. During the symposium, a wide array of tissue systems, including cardiovascular, gastrointestinal, urologic, dermatologic, musculoskeletal and the central nervous system were discussed with plenary sessions focused topics such as, whole organ engineering, variables that influence the host remodeling response, fundamental concepts of cell-scaffold interactions, tissue source and  processing/manufacturing methods, role of the innate immune response and outcomes of human clinical applications. The symposium offered the opportunity for clinicians and researchers to  present new data on the use of biologic scaffold materials for regenerative medicine applications, which has application to patients who have had an amputation or have  a large scale tissue loss.² 

³Meng FW, Slivka PF, Dearth CL, Badylak SF. Solubilized extracellular matrix from brain and urinary bladder elicits distinct functional and phenotypic responses in macrophages. Biomaterials. 2015 Apr;46:131-40. doi: 10.1016/j.biomaterials.2014.12.044. Epub 2015 Jan 24.

Extracellular matrix (ECM) scaffolds derived from a variety of source tissues have been successfully used to facilitate tissue reconstruction following injury. The present study evaluated the effect of solubilized ECM derived from brain and urinary bladder tissues. Results suggest that the molecular composition of the source tissue ECM plays an important role in influencing macrophage function and phenotype. These findings providing additional evidence to support the rational design of next generation regenerative medicine materials to facilitate more efficient restoration of injured extremity tissue.³

⁴Garg K., Ward C. L., Hurtgen B. J., Wilken J. M., Stinner D. J., Wenke J. C., Owens J. G., & Corona B. T. (2015). Volumetric muscle loss: Persistent functional deficits beyond frank loss of tissue. Journal of Orthopaedic Research, 33(1):40-46. doi: 10.1002/jor.22730

Open fracture is a common occurrence in civilian and military populations and often results in persistent muscle strength deficits and diminished limb function.   There are, however, many questions remaining regarding the pathophysiology of the volumetric loss of skeletal muscle. The study demonstrated in a rat "open fracture" model, that the volumetric loss of skeletal muscle results in persistent functional deficits that are dependent on muscle length and joint angle. Objective data from a patient with an open type III tibia fracture resulting in volumetric muscle loss was also presented, with the patient demonstrating persistent functional deficits that are similar to those observed in the animal model. The persistent loss of limb function following volumetric muscle loss is likely due, in part, to persistent changes in muscle architecture.⁴